Ignition apparatus



Oct. 19, 1943. G. D. FRANK' IGNITION APPARATUS Filed March 20, 1942Patented Oct. 19,1943 1 IGNITION APPARATUS .George 1). Frank, York,-Pa.,assignor to .York OH Burner '00., Inc., York,

Delaware 'Pa., a corporation of Application MarchZO, 194,2,Serial No.435,554

It is an object of this invention to provide an igniter which isdesigned .to 'directaa hot ignition flame against an atomized .oil andair, or other combustible, mixture as the.mixture is projected fromburner apparatus into the combustion chamber of a furnace.

It is the further object of :this invention to provide a torch-typeigniter which is completely closed to the outside atmosphere, therebypreventing all possibility of a flare or pufi-back through the igniterfrom the furnace combustion chamber to theoutside of the furnace.

Another object -'of this invention is to provide an economical igniterof the gas-electric .type for intermittent operation on manufactured,natural, "bottled or any other gas supply, and which requires nocontinuously burning :pilot light.

'It is a further object of this invention to provide a'torch-type'i'gniter apparatus which will be continually purged by a current offresh forthe walls of air during the operation o'f' the main burner-toprevent fouling and/ or overheating of theigniter parts bythe'combustion gases prevailing in the furnace chamben.

It is a further object of th invention toprovide an igniter constructionwhich may be-easily disassembled for inspection and adjustment, andwhich has a minimum'numberof parts and is economical to manufacture andinstall.

Still another object is to providea-gas-electric type of igniterwhichis-of such construction as to beparticularly' eficient'in igniting'theigniter charge.

A still further object is to provide a gas-electric type of 'igniterwith novel-and efficient means for mixing air and gas to be ignited.

Another object is to provide a gas-electric type of igniter of suchconstruction that the igniter electrode points are both cooled andshielded from the igniter flame by-a jet of air.

Other objects andadvantages'of this invention will be apparent from thefollowing description of the embodiment of the .invention illustrated inthe accompanying .drawing, inwhich:

' Figure 1.is:a;top'-.plan view, partly in horizontal cross-section,showing one-method of installing an ignition apparatus embodying thepresent inventionnthe ignition .apparatus being illustratedasinst'alledin the front wall of a furnace and adj acent arhorizontaltype rotary oil burner;

Figures? is a vertical section viewof the-ign'iter apparatus .of Figure1;

Figure 3 is. a crosssectional view taken on line 2i3 of :Figure .2;

Figures 4 and :5 are end .andperspectiveviews respectively :'of "the airand ,gas nozzle, structure of Figures .2 and 3. Figureiis also a-viewtaken on linen-4i 'ofFigure 2.

.Referringto Figure 1 of the drawing, ahorizontal rotary oil burner isindicated generally bythe numeral I 0. The burneris usuallypivotallymounted on the front wall H of a furnace in aiconventionalmanner byhinge I2 and clamp i3. The burner 10 is;provided witha rotaryoil cuphl 'and a centrifugal fan 15 for projecting a combustible mixtureof atomized oil .and air intothe entrance IB of a furnace combustionchamber. The ignition apparatus is 'mounted partly within a passage l'lvthrough or.in thefurnace 'wall H, and a lining l8 may be providedpassage lz'i. The ignition apparatus comprises a housing 113 .havingaremovable closure or end plate .20 out side *of the furnace wall andadjacent the oil burner Hi and :may include a ltubularzportion 2{extending into the passage 11. lIhethousing J9 is-convenientlysupported'rby a bracket-Hsecured to -.an angle plate 23 on the frontwall of thefurnace.

The ignition housing 19,;shown in-section'in Figures .-2.and.3, isprovided with a tubular-0r nozzle-likeportion 2 l to :be directed towardthe entrance to theiicombustion chamber of "the furnace. .An'appropriate relationship of ignition apparatus anduburner is illustratedin zl figure l. The tubular portion 2| may extend .into or to thecombustion chamber, or it may terminate short of the combustion chamberentrance at any point in'passage I l. 'iObvi'ously, thenozzlaportion' il,as wll asthe passage 1 H mayrbe of i-any desired cross-'sectiomracircularcross-section being preferred. A somewhatcenlarged chamber 23 isprovidedat the opposite or :outer end of the housing 1-9, and is .closedby the removable end pIate ZU-Which is secured to:the.housing:.l 9 byscrews 2501 the like. 1 1

Gasis supplied by a -pipe 2 6 'to a :gas :nozzle or tube *2-1 within thechamber :24. The-source of this gas may be any available supply ofmanufactured, bottled, or natural gas and may be connected to the pipe26 by conventional conduits and valves. The gas nozzle 21 is supportedby the closure plate 2d, the inlet end of the nozzle 21 having threadedengagement with the plate 20 as shown in Figures 2 and 3. The gas pipe26 also has threaded engagement with the closure plate 20. Acommunicating passage between the pipe 23 and the gas nozzle 21 iprovided by the bores 28 and 23 which are formed in the plate 23. Thetip or discharge end 3|! of the gas nozzle 21 is modified or partiallyflattened as shown in the drawing and for a purpose to be described.

A nozzle or tube 3| is supplied with air by a pipe 32 which may beconnected to any suitable source of air under pressure, but preferablyis connected to the main burner fan casing 33 for supplying air underpressure'above atmospheric pressure. The pipe 32 may be connected in anysuitable and convenient manner to the fan casing 33, so that during theentire operation of the fan Hi the pipe 32 will supply the nozzle 3|with air-under pressure. The outlet end of pipe 32 has threadedengagement with the closure plate 23, and also has close interfittingconnection with the inner end of the air nozzle 3|. Thus the air nozzle3| is supported by air pipe 32, and is maintained in operative positionby reason of the threaded engagement of the pipe 32 with the closureplate 22]. This nozzle 3| extends along the interior of the gas nozzle21 and is also spaced from the inner Walls of the gas nozzle 2'1. Thetip 34 of the air nozzle 3| extends outwardly of and beyond the gasnozzle tip 30 and is modified or partially flattened similarly to thetip 30, but at a right angle thereto as will be seen from the drawing.

The end or closure plate 23 also carries the high tension insulatingbushings 36, 31 which are held in place by nuts 33, 39. The bushings 35,31 support spark gap electrodes 4%], 4| adjacent the nozzle tips 30 and3-2. The two bushings 36 and 31 are mounted at opposite sides of thebore 23 and have their electrodes 43, 4| extending toward each other.The tips or points of the electrodes 46, 4| are positioned in the pathof air discharged by the air nozzle 3| and closely adjacent the airnozzle tip 34. The electrode tips or points preferably are spaced aparta distance on the order of three sixteenths of an inch and supplied withcurrent to provide a 10,000 volt are between the points. The electrodes40, 4| are intended to be connected through terminals 42, 43 to atransformer or other suitable source of high potential electricity.

The end closure plate 23, the nozzles 21, 3|, and the electrodes 40, 4|with their supports form a unit which is removable from the igniterhousing IQ for inspection, adjustment or cleaning. This unit may beremoved from the housing H! by removing the screws 25 which secure theplate 20 to the housing l9.

Operation When it is desired to operate the main burner M, the burnermotor is started either manually or thermostatically by conventionalcontrols. Operation of the main burner fan l supplies air to thecombustion chamber and also conveniently supplies air through the pipe32 to the air nozzle 3|. The igniter is also manually or automaticallystarted by admitting gas through the pipe 26 to the gas nozzle 21 andsupplying electric current to produce a spark or are between the pointsor outer ends of the electrodes and 4|. The gas issuing from the nozzle21 is ignited by the electric spark or are, and the flame is carried orblown to the combustion chamber end of the passage I! by means of theair jet issuing from the air nozzle 3|. The igniter produces a hotblow-torch flame at the combustion end of the passage H. The main oilsupply is then turned on and the combustible mixture of oil and air, orthe like, projected by the burner into the combustion chamber is at onceignited by the hot intense flame supplied by the igniter. The supply ofgas and electricity to the igniter may then be discontinued and theigniter thereby extinguished. However, a current of air under pressureis continuously supplied to and passes through the igniter housingduring operation of the main burner.

The igniter provides a relatively long and strong electric spark whichis adapted to ignite various types of gases ranging, for example, frombottled gas having a B. t. u. content of 2,500 units per cubic foot to alower grade of manufactured gas having only 350 B. t. u. per cubic foot.The igniter requires no adjustment to adapt it to these various gases,although the gas flow to the igniter may be regulated by a throttlingvalve in the main supply pipe and in accordance with the particular typeof gas being used. The electric arc is formed directly in front of theair nozzle tip 33 and directly across the air jet. The are assumes alooped shape, and the moving air between the electrode tips tends tomake the arc flutter. Thus a relatively wide band of igniter action isprovided for the electric arc.

Due to the shape of the air nozzle tip 34, the air jet issuing therefromspreads out in a fan shape and in a direction lengthwise of theelectrode tips or points. As the electrode points project into this fanshaped air stream, they are kept cool by the flowing air. The aircurrent also tends to keep the ignition flame stable and away from theelectrode points. In this way, the air flow not only exerts a coolingeffect on the electrode points but also shields them from the burnerflame. The action of the air stream on the electrode tips or points isan important feature, since sulphur, which is usually present in theigniter gas, will cause excessive and objectionable corrosive action atthe electrode tips if they are allowed to remain in the ignitercombustion area. The air current also tends to blow away any car- I bondeposits which might form on the electrode tips and cause shortcircuits.

Since the air nozzle 3| is positioned within the gas nozzle 27, the gasjet issuing from the gas nozzle 21 is delivered as an envelope orblanket surrounding the air jet. As the gas nozzle tip 33 is partiallyflattened, the gas issuing therefrom also spreads out in a fan shape,the spreading action of the gas being in a direction (or plane) at rightangleslnormal) to the direction (or plane) in which the air jet spreadsin a fan shape. Due to the relative arrangement and shape of the nozzletips 33, 3 1, the gas and air jets are so discharged as to providethorough intermixing of the gas and airand to promote and insureignition of the gas, even though the air and gas are not introduced inthe most suitable proportions for securing combustion.

Since the housing |9 including enlarged chamber 24 is closed by endplate 23, there is no possibility of puff-back or flare-back from thecombustion chamber through the igniter housing to the outside of thefurnace. The continual current 'offre'sh air passingthrough the igniterchamber and housing during operation 'of the main burner purges andcools theigniter and maintains it at all times in readiness forrelighting. The air current alsoserves to prevent combustio'n gases fromentering the igniter housing from the furnace combustion chamber, andthereby'eliminates overheating, burning, or fouling oi'the igniteiparts. Since gas is supplied to the igniter nozzle 2-7 only during themain bur'ne'r starting operation, there 'is no continuously burningpilot flame, and hence gas consumption is minimized. In the "event offailure of the main burner fanto operate When'theburnor is started, theigniter gas supply will be lighted, but it will burn with only a small"flame 'at'the tip of the gas nozzle 2?, and hence not effective to"cause ignition in the furnace combustion chamber until the main burnerfan operates satisfactorily. A further advantage of the abovedescribedigniter construction is the fact that the sparlsgap beingin a closedchamber is adequate iy protected from mechanical injury as well as fromheat and corrosion.

Other advantages of my improved apparatus will be readily apparent fromthe above description of anembodiment thereof. Obviously, variations inthe nature and arrangement of the elements described will be evident tothose skilled in'this art, and this invention contemplates anyequivalent structure within the scope of the following claims.

Having described my invention, what I claim anddesire to secure byLetters Patent is:

l. Ignition apparatus for use with a furnace having a combustion zone,and a burner and fan for supplying a combustible mixture to said zone,said ignition apparatus being adapted for positioning adjacent said zoneand adapted to blow an ignition flame against said combustible mixture,said ignition apparatus comprising a housing having a flame outlet forcommunicating with said combustion zone, said housing being closed tothe atmosphere outside of said combustion zone, an air nozzle mountedwithin said housing to discharge a jet of air into said flame outlet,means for conducting air under pressure above atmospheric pressuresupplied by said fan to said air nozzle, electrode means in said.housing and positioned to provide the sparking end thereof closelyadjacent said air nozzle and in the path of said air jet, and means forsupplying said housing with gaseous fuel for ignition by the spark ofsaid electrode means.

2. Ignition apparatus for use with a furnace having a combustion zoneand a burner for supplying a combustible mixture to said zone, saidignition apparatus being adapted to blowan igniting flame against saidcombustible mixture, said ignition apparatus compising: a housing havingan ignition flame outlet for positioning at an opening in a Wall of thefurnace, a gaseous fuel nozzle Within said housing and positioned todirect a gaseous fuel jet toward said ignition flame outlet, meansdisposed substantially centrally of the outlet of said fuel nozzle todischarge a stream of air into said gaseous fuel jet and toward saidignition flame outlet, means for supplying air under pressure aboveatmospheric pressure to said air discharge means, and spark electrodesWithin said housing and having the points thereof closely adjacent saidair discharge means and in the path of said air jet.

3. Ignition apparatus for use with a furnace having a combustion zoneand a. burner for supplying a combustible mixtur'e to 'said'zone, saidignition apparatus being adapted to be positioned at an opening in awall of the furnace and to blow an igniting flame against saidcombustible mixture; said ignition apparatus comprising: ahoflsinghaving a chamberand an elongated tubular portion extending fromone end of said chambe'm'fa plate-forming a removable closure for theopposite end of said'chamber; a gaseous fuel supply tube within "saidchamber, supported by said plate, a nd having the outlet thereofpositioiied to direct a jet of gas into said tubular portion; an airsupply tube within and extending axially of said gaseous fuel tube todirect a jet of 'airinto' said tubular portion; insulating bushingscarried by said plate at opposite sides of said-gaseous rueltube; and'spark electrodes supported by said bushings and within said chamber,the p'oints of said electrodes being arranged closely adjacent thedischarge end of air tube and in the path of said air jet.

4. A structure as recited in claim 3, wherein t-hedischarg'e'ehd's ofthe air and gas nozzles are shaped to provide air and gas jets of fanshape, s'aidgas jet h'aving it's longer cross sectional dimension'exte'nding at an angle to the longer cross sectionaldirnension of saidair jet to pro vide thorough int'ermixing thereof, the spread of saidair j'et into fan-shape being in the same plane as the electrode points.

5. Ignition apparatus for use with a furnace having a combustion'zoneand a burner for supplying a combustible mixture to said zone, saidignition apparatu being adapted to blow an igniting flame against saidcombustible mixture, said ignition apparatus comprising: a housing, agaseous fuel supply tube'within said housing, an air supplytubeextending along the interior of saidgaseous fuel supply tube and havingthe dis charge end thereof extending outwardly of the discharge end ofsaid gaseousfuel tube, spark electrode means Within said housing andpositioned to provide both the sparking end thereof and'the'electric arcproduced thereby closely adiacent said air tube discharge end and in thepath of the air jet issuing from said air nozzle, and means forsupplying air under pressure above atmospheric pressure to said airtube.

6. Ignition apparatus for use with a furnace having a combustion zoneand a burner for supplying a combustible mixture to said zone, saidignition apparatus being adapted to be positioned at an opening in awall of the furnace and to blow an igniting flame against saidcombustible mixture, said ignition apparatus comprising: a housinghaving a chamber and an elongated tubular portion extending from one endof said chamber; a plate forming a removable closure for the oppositeend of said chamber; a gaseous fuel supply tube within said chamber,supported by said plate, and having the discharge end thereof positionedand shaped to direct a fanshaped jet of gaseous fuel toward said tubularportion; an air supply tube positioned within and extending axially ofsaid gaseous fuel supply tube, the discharge end of said air supply tubeextending through and beyond the discharge end of said gaseous fuel tubeand being positioned and shaped to direct a fan-shaped jet of air intosaid tubular portion; said fan-shaped gaseous fuel jet spreading in aplane substantially normal to the plane of spread of said air jet; and aset of spark electrodes carried by said plate, the points of saidelectrodes being arranged closely adjacent said air tube discharge endand positioned in the path of said air jet.

7. Ignition apparatus for use with a furnace having a combustion zoneand a burner for supplying a combustible mixture to said zone, saidignition apparatus being adapted to be positioned at an opening in aWall of the furnace and to blow an igniting flame against saidcombustible mixture, said ignition apparatus comprising: a housinghaving a chamber and an elongated tubular portion extending from one endof said chamber; a plate forming a removable closure for the oppsite endof said chamber; a gaseous fuel supply tube within said chamber,supported by said plate, and havin the dischar e end thereof positionedand shaped to direct a fanshaped jet of gaseous fuel toward said tubularportion; an air supply tube positioned within and. extending axially ofsaid gaseous fuel supply tube, the discharge end of said air supply tubeextending through and beyond the discharge end of said gaseous fuel tubeand being positioned and shaped to direct a fan-shaped jet of air intosaid tubular portion; and a set of spark electrodes carried by saidplate, the points of said electrodes being arranged closely adjacentsaid air tube discharge end and positioned in the path of said air jet,said fan-shaped air jet spreading in a plane extending through saidelectrode points and substantially normal to the as j 8. Ignitionapparatus for use with a furnace having a combustion zone and a burnerfor supplying a combustible mixture to said zone, said ignitionapparatus comprising: a housing having a chamber and an elongatedtubular portion extending from one end of said chamber, said tubularportion being adapted to be positioned at an opening in the wall of thefurnace to direct an igniting flame against said combustible mixture; aplate forming a removable closure for the opposite end of said chamber;a gaseous fuel supply tube within said chamber, supported by said plate,and having the discharge end thereof positioned and shaped to direct afan-shaped jet plane of spread of said end of said gaseous fuel ofgaseous fuel toward said tubular portion; an air supply tube positionedwithin and extending axially of said gaseous fuel supply tube, thedischarge end of said air supply tube extending through and beyond thedischarge end of said aseous fuel tube and being positioned and shapedto direct a fan-shaped jet of air into said tubular portion; a set ofspark electrodes carried by said plate, the points of said electrodesbeing arranged closely adjacent said air tube discharge end andpositioned in the path of said air jet; said fan-shaped air jetspreading in a plane extending through said electrode points andsubstantially normal to the plane of spread of said gas jet; and meansfor supplying air under pressure above atmospheric pressure to said airsupply tube.

9. Ignition apparatus for use with a furnace having a combustion zoneand a burner for supplying a combustible mixture to said zone, saidignition apparatus being adapted to be positioned at an opening in awall of the furnace and to blow an igniting flame against saidcombustible mixture, said ignition apparatus comprising: a housinghaving a chamber and an elongated tubular portion extending from one endof said chamber; a gaseous fuel supply tube within said chamber andhaving the discharge end thereof positioned and shaped to direct afan-shaped jet of gaseous fuel toward and into said tubular portion; anair supply tube positioned within and extending axially of said gaseoufuel supply tube, the discharge end of said air supply tube extendingthrough and slightly beyond the discharge tube and being positioned andshaped to direct a fan-shaped jet of air into said tubular portion; saidfan-shaped gaseous fuel jet spreading in a plane substantially normal tothe plane of spread of said air jet; and a set of spark electrodeswithin said housing, the points of said electrodes being arrangedclosely adjacent said air tube discharge end and positioned in the pathof said air jet to form an arc extending in the plane of said air jet.

GEORGE D. FRANK.

